Details

Description:
Firefox reports that it 'cannot connect to server', this happens for only a few servers. Links browser and firefox on windows (without the network.dns.disable.IPv6=TRUE) will connect without issue.
The url below is an example, that will not work on the freshly installed firefox 12.0-2 package on Arch 64. The url will work on Links text browser and on firefox under windows without any config modifications.
No modifications to the configs of the above are done before trying, after changing the setting for Arch firefox the url (or server) will work.